Becoming your own fortune teller: what hands can tell you

Second-year Psychology students participating in the University Honours College complete a Research Seminar, during which they write a popular science article about their second-year research internship. The article voted best one of this year was by Sophie Lammerink. Mindwise publishes a modified version of her article.

Imagine you’re going on a first date, and you are having a really good time. Then all of a sudden, your date takes your hand. At first you think this is a romantic gesture. But then your date takes a ruler from his or her pocket and starts measuring your index finger and your ring finger. Sounds weird? Well, you better continue reading because after you’ve read this article, you’ll realize that the person with the ruler should be you.

The ratio between the length of your index finger and your ring finger is known as the 2D:4D ratio. This ratio is considered an indicator of the extent to which you were exposed to testosterone as a developing foetus in the womb. High levels of testosterone have been associated with a low 2D:4D ratio, and the other way around. Supposedly, the shorter your index finger compared to your ring finger, the more masculine you are, regardless of whether you are male or female.

Over the past several years, the 2D:4D ratio has been topic of many studies. Findings suggest that the 2D:4D ratio is associated with various personality traits, ranging from agreeableness to aggressiveness to assertiveness. According to a study conducted in France, people with a lower 2D:4D ratio are less trustworthy than people with a higher 2D:4D ratio (Bonnefon, De Neys, & Hopfensitz, 2013). Moreover, people with a lower 2D:4D ratio may be more likely to experiment with alcohol, drugs, and sex (Manning & Fink, 2011) and seen as less nice (Dane, 2010). However, a lower 2D:4D ratio has also been associated with higher attractiveness, especially in men (Russell, 2006).

“men with lower 2D:4D ratios were less quarrelsome towards women than towards men”

While there has been quite some research assessing the relation between the 2D:4D ratio and personality, most of this research took place in the laboratory and at a single time point. In comparison, Moskowitz, Sutton, Zuroff & Young (2015) recently conducted a study in which the behaviour of working adults was measured in their daily lives over a period of 20 days. Participants were instructed to complete paper forms after every social interaction they had in their lives, and check which behaviours they engaged in during the social interactions. The study found no relation between 2D:4D ratios and behaviour for women. In contrast, men with lower 2D:4D ratios engaged in more agreeable behaviours and fewer quarrelsome behaviours than men with higher 2D:4D ratios. Moreover, men with lower 2D:4D ratios were less quarrelsome towards women than towards men, whereas men with higher 2D:4D ratios were equally quarrelsome towards men versus women. Moskowitz et al. (2015) speculated there might be a link between these findings and those of a previous study in which men with lower 2D:4D ratios tended to have more children (Manning & Fink, 2008). Being more agreeable and less quarrelsome, especially towards women, may be beneficial for initiating and maintaining relationships with women, which may then increase the likelihood of having children.

“Being more agreeable and less quarrelsome, especially towards women, may be beneficial for initiating and maintaining relationships with women, which may then increase the likelihood of having children.”

In the past year, together with fellow Honours students Jana Uppendahl and Lenka Wichmann, I was involved in a study supervised by Dr. Marije aan het Rot which tried to extend these findings to first-year Groningen Psychology students. We used the same questionnaires as Moskowitz et al. (2015) for measuring behaviour during social interactions, except we administered them using an online web application installed on participants’ smart phones. The data haven’t been analysed yet, but are expected to be similar for the men. For the women, if we do find a relation between 2D:4D ratios and behaviour, the difference might be explained by the difference in age: the women in the Canadian study were older, and therefore more likely to have had children.

So now that I have told you what fingers can tell you about a person, you might want to take a closer look at the hands of your friend, your brother, or your neighbour, and try to predict their futures. You can try this at home, but I warn you! Measuring someone’s 2D:4D ratio with the naked eye is not easy. In our study, we used hand scans so we could measure the lengths of the fingers very precisely, using sophisticated software. So next time you go out on a first date, you might want to stop at the copy shop instead of bringing a ruler.

Russell, D. (2006). Raise your hand if you think I am attractive: Second and fourth digit ratio as a predictor of self- and other-ratings of attractiveness. Personality and Individual Differences 5(40), 997-1005.

Sophie Lammertink is a third-year Psychology and Honours student at the University of Groningen. Happy to be challenged and eager to learn, she very much enjoys studying at university. Within the field of psychology, she is mainly interested in forensic and clinical psychology. In her third year, Sophie will take a Crime and Punishment minor at the Law Faculty, during which she will learn how psychology and law are related. Even though studying takes up a lot of her time, she enjoys multiple hobbies in her free time. Whenever possible, you can find Sophie hanging out with friends, practicing various sports ranging from volleyball and windsurfing to scuba-diving, or travelling to all the corners of the world.